The present invention relates to a solenoid control valve and a control method.
Internal combustion engines for motor vehicles are known which include a hydraulic system for performing work in addition to lubrication. This work can be used to activate/deactivate cylinders of an internal combustion engine to conserve fuel. Such a hydraulic valve lifter activation/deactivation system can include a hydraulic control valve in a valve housing mechanically connected to a separate solenoid. The solenoid includes a solenoid coil bobbin on which a wire coil is wound and an armature that moves the control valve in response to an input signal (coil electrical current signal) to the wire coil to control hydraulic pressure in the valve lifter oil control gallery. A separate check valve assembly is mounted in a fluid exhaust passage (vent-to-sump) in the engine block or cylinder head and functions to maintain oil pressure in the oil control gallery at a preselected minimum value. Such engine oil control solenoids comprise numerous components which must be assembled together and are known to suffer from hydraulic fluid (oil) leakage through various paths around the solenoid housing.
The Seid and Najmolhoda U.S. Pat. No. 6,209,563 describes a solenoid control valve having a molded one-piece valve nozzle and coil bobbin member that includes an integral check-valve receiving receptacle communicated to an exhaust port.
Copending application Ser. No. 09/480,196, now U.S. Pat. No. 6,321,767, also describes a solenoid control valve. A coil bobbin region and check valve-receiving receptacle are formed on a molded one-piece member. A nozzle or port-forming member having a spool valve therein is received in an open end of the one-piece member.
Engine oil solenoid control valves are communicated to the valve lifter oil control gallery (i.e. receive supply pressure) such that ferrous (paramagnetic) particles in the engine oil supply may migrate or pass through the supply port filters of the control valve to the solenoid air gap where they can adversely affect performance and life of the control valve by restricting spool stroke.
An object of the present invention is to provide an improved a hydraulic fluid solenoid control valve that traps or getters ferrous particles in the hydraulic fluid supplied to one or more supply port(s) of the control valve.
The present invention provides a hydraulic fluid solenoid control valve, such as in one embodiment, an engine oil solenoid control valve, having a solenoid coil, a solenoid armature movable by energization of a solenoid coil, a check valve communicated to a fluid exhaust port of the control valve, a fluid control valve movable relative to a fluid control port in response to armature movement, and a permanent magnet disposed relative to one or more fluid supply ports of the control valve to magnetically capture or getter ferrous particles in hydraulic fluid supplied to the supply port(s).
In an illustrative embodiment of the invention, the solenoid control valve includes a molded one-piece member that defines a check valve-receiving receptacle and a coil bobbin region of the solenoid. The molded one-piece member includes an end proximate the check valve-receiving receptacle that receives a fluid port-forming and spool-receiving sleeve member that provides the fluid supply port and fluid control port. A spool valve is received in the port-forming sleeve member and includes a spool valve end connected to the armature of the solenoid. The spool valve moves in response to movement of the solenoid armature in response to electrical current signals supplied to the solenoid coil. The spool valve includes first and second lands that are moved relative to the respective fluid supply port and control port to control fluid flow at the control port.
The sleeve member includes the ferrous particle-capturing permanent magnet on an end of the sleeve member that is received in a fluid supply bore of an internal combustion engine block or cylinder head to remove ferrous particles from the hydraulic fluid. The permanent magnet is disposed on the sleeve member in the supply bore at a location upstream of the supply port. The permanent magnet can have a disc or annular ring configuration and be fastened on the end of the sleeve member by adhesive, press fit, crimping, and other suitable fastening technique. The permanent magnet can comprise any suitable permanent magnet material to magnetically attract and hold ferrous particles in the hydraulic fluid before the particles can enter the fluid control valve.
The foregoing and other objects, features, and advantages of the invention will become apparent from the following more detailed description taken with the accompanying following drawings.